Oral care researchers have established that frequent delivery of xylitol molecules in the mouth can reduce caries, gingivitis, periodontitis, halitosis and inner ear infections by suppressing the growth of certain bacteria. These bacteria thrive on certain carbohydrate molecules such as sucrose, glucose, fructose and other sugars but, when they ingest the xylitol molecules, they cease proliferating and cease to adhere to human tissues. Delivering xylitol molecules in the mouth also provides other benefits, such as remineralization of teeth and reduction of plaque and halitosis by stimulating saliva flow.
For these reasons, chewing gum, lozenges, and lollipops have been developed that have high levels of xylitol. These products are sold to consumers with instructions to keep the gum or candy in their mouths over time, so long as xylitol is being released, but this is typically less than five minutes for chewing gum and less than 15 minutes for lozenges and lollipops.
Mints, lozenges, and lollipops may be technically described as “troches”. For treatment of health problems in the mouth or throat, people have for centuries held in their mouths a composition containing medication for topical application. Since the middle ages, the name for such a composition, derived from Latin and previously from Greek, is “troche”. A modern form of troche is the cough drop, so named because it was formed by “dropping” hot, viscous, sugar-based candy onto a sheet or into a mold where it cools to form the troche. Another modern form of troche is the “lozenge”, so named because it was in the shape of a diamond (like on playing cards), which is the meaning of the word “lozenge”. A troche is large enough that a person is able to track where it is in the mouth and move it with their tongue, that is, larger than about 5 mm in at least two dimensions. Xylitol troches dissolve quickly and are insignificantly adherent in a human mouth.
For release of xylitol in the mouth over time, some people will prefer chewing gum and some people will prefer a troche, such as a lozenge or lollipop. There is a need for a third alternative, an adherent troche that will remain adhered to a spot in the mouth, such as a tooth, while the troche dissolves releasing xylitol or a similar polyol. And there is a need to slow the rate of dissolution to maintain therapeutic levels of xylitol or other polyol in the fluids of the oral cavity over longer periods of time.
U.S. Patent 6,139,861 issued to Mark Friedman surveys methods for adhering a troche to a location within the mouth. These methods include two forms of adherent troches, referred to by Friedman as a “mucoadhesive erodible tablet”. These tablets are formed using polymers carboxymethylcellulose, hydroxymethylcellulose, polyacrylic acid, and carbopol-934. Another form of adherent troche is a flexible device, often called an “oral patch.” Examples include the adherent, soluble oral patch disclosed by the same inventor in U.S. patent application Ser. No. 10/287,843 filed Nov. 5, 2002, which is incorporated herein by this reference, and multi-layer patches, such as those disclosed in PCT patent application serial number PCT/US2007/005947 (applicant reference 0795-030-04) by the same inventor entitled Multi-layer medical patch with impermeable center filed Mar. 7, 2007 which is incorporated herein by this reference.